How successful is fetal echocardiographic examination in the first trimester of pregnancy?

OBJECTIVE

Transvaginal echocardiography is still rarely incorporated into the first-trimester ultrasound examination, despite the fact that heart defects are the most frequently encountered congenital malformation. This study was undertaken to explore the possibilities of fetal echocardiography in the late first trimester.

METHODS

In 85 women with uncomplicated singleton pregnancies, three transvaginal ultrasound examinations between 11+0 and 13+6 weeks' gestation were performed. The examinations were carried out at weekly intervals and visualization of several echocardiographic planes was attempted (four-chamber view, aortic root, long axis of the aorta, pulmonary trunk with three-vessel view, cross-over of the great arteries). The diameter of the aorta and pulmonary trunk were measured to establish reference ranges.

RESULTS

The success rate of visualization of the different parameters increased with gestational age. The ability to perform a full cardiac examination increased from 20% in week 11 to 92% in week 13. Longitudinally derived growth curves of the aorta and the pulmonary trunk were constructed and both showed a linear increase with gestational age.

CONCLUSIONS

The best time in the first trimester to perform transvaginal echocardiography is at 13+0 to 13+6 weeks' gestation. In this period, a full cardiac examination is possible in 92% of cases. The increase of success rate compared to earlier studies is likely to result from the use of better resolution, high-frequency transvaginal probes. First-trimester echocardiography provides an opportunity to examine the fetal heart early in gestation, especially in patients at risk for cardiac malformations because of a positive family history or in fetuses with increased nuchal translucency.

Cardiac malformations in first-trimester fetuses with increased nuchal translucency: ultrasound diagnosis and postmortem morphology

OBJECTIVE

The aim of this study was to explore the diagnostic accuracy of first-trimester transvaginal echocardiography in fetuses with increased nuchal translucency (NT) thickness, by comparing the ultrasound diagnosis with the findings on postmortem examination or mid-gestational ultrasound and neonatal outcome.

METHODS

Transvaginal echocardiography was performed in 45 fetuses with a NT > 95th centile. Karyotyping was performed in 43. In 20 of the 23 pregnancies in which termination of pregnancy was carried out, postmortem examination was performed to determine the presence and type of heart defect. Mid-gestational echocardiography was performed in ongoing pregnancies and neonatal follow-up information was obtained. Findings on first-trimester transvaginal echocardiography were compared to those of second-trimester echocardiography or the results of postmortem examination. The mean NT in the fetuses with and without heart defects was calculated.

RESULTS

Of the 45 fetuses, heart malformations were suspected on first-trimester ultrasound in 10 (22%), of which eight (80%) were found to have a chromosomal abnormality. Postmortem examination showed minor additional findings in some cases and major discrepancies occurred in none. Septal defects were the most common defects in trisomic fetuses. In three fetuses with a 45 X karyotype, hypoplastic left heart syndrome was diagnosed. Heart defects were diagnosed in three euploid fetuses in which fetal demise occurred. The sensitivity and specificity for the detection of heart defects of transvaginal echocardiography were 88% and 97%, respectively. The mean NT in fetuses with a normal heart (4.3 mm) was significantly smaller than that of fetuses with heart defects (7.4 mm).

CONCLUSION

Transvaginal echocardiography can be performed reliably in first-trimester fetuses with an increased NT. In this study, the proportion of chromosomally abnormal fetuses with a heart defect was not different from that found in newborns, except for cases of Turner syndrome. Fetal demise occurred in all three euploid fetuses with a heart malformation. The fetuses with a heart defect had a larger NT than did those without.

First trimester diagnosis of split hand/foot by transvaginal ultrasound

OBJECTIVE/METHOD

First trimester high-frequency transvaginal ultrasonographic examination was performed in a 26-year-old gravida 2, para 1, diagnosed with tetramelic split hands and feet. The couple was informed about the probable 50% recurrence risk of this anomaly.

RESULTS

At 12 weeks' gestation, high-frequency transvaginal ultrasound examination revealed a fetus with biometry consistent with gestational age. Both hands appeared to have a single digit at the ulnar side. On the site of the metacarpal bones, only three bones could be visualized. Both feet showed two digits, with a typical 'split-foot' appearance. Nuchal translucency thickness measured 1.0 mm. No additional abnormalities could be found. The child was born in good condition with the described split hand/foot malformation (SHFM).

CONCLUSION

This case report demonstrates prenatal sonographic diagnosis of SHFM in a first trimester fetus. In first trimester there can be several technical advantages and it shortens the period of uncertainty of the parents. Secondly it provides the option of early surgical termination of the pregnancy instead of induction of labour.

Acute maternal rehydration increases the urine production rate in the near-term human fetus

OBJECTIVE

We sought to investigate the effect of a decrease of maternal plasma osmolality produced by hypotonic rehydration on the fetal urine production rate in normal near-term human fetuses.

STUDY DESIGN

Twenty-one healthy pregnant women attending the clinic for antenatal care were studied between 37 and 40 weeks' gestation. The fetal urine production rate was assessed by serial measurements of 3 diameters of the fetal bladder. The hourly fetal urine production rate was determined by linear regression analysis of the calculated bladder volumes versus time and was initially determined after a period of 4 hours of fluid deprivation. Thereafter, the women were asked to drink 1 L of water, and the hourly fetal urine production rate was assessed again. The hourly fetal urine production rate was only studied during behavioral state 1F because it is dependent on the behavioral state. The fetal behavioral state was determined by assessment of fetal heart rate, fetal eye movements, and fetal body movements.

RESULTS

Successful recordings were obtained in 10 of the 21 women. The hourly fetal urine production rate increased significantly after hypotonic rehydration (P <.02). Compared with the initial hourly fetal urine production rate after 4 hours of fluid deprivation, the hourly fetal urine production rate showed an increase of 63.2% after hypotonic rehydration, from 38.2 +/- 16.3 mL/h to 62.4 +/- 34.6 mL/h (mean +/- SD). After rehydration, the baseline fetal heart rate fell significantly, from 141 +/- 6 to 132 +/- 8 beats/min (mean +/- SD; P =.005).

CONCLUSION

The fetal urine production rate is augmented after acute maternal oral hypotonic rehydration after 4 hours of fluid deprivation. The current findings demonstrate that the near-term human fetus can handle such acute changes in fluid osmolality by increasing the urine production rate to maintain its fluid homeostasis. This mechanism implies that changes in maternal plasma osmolality and volume probably play an important role in determining amniotic fluid volume. Therefore the application of maternal hydration for the treatment of oligohydramnios should be further investigated.

Pathophysiology and treatment of fetal anemia due to placental chorioangioma

Placental chorioangiomas occur in 1% of pregnancies. Large chorioangiomas may cause serious complications such as fetal anemia, hydrops and fetal death. In this case report, a pregnancy complicated by a large placental chorioangioma is described. Severe fetal anemia without the occurrence of hydrops fetalis was suspected using ultrasound and Doppler examinations. Successful intrauterine blood transfusion was performed, with an unusually large amount of blood needed to obtain an adequate rise in fetal hematocrit. Two weeks later, at 32 weeks, the infant was born in good condition. In pregnancies with large chorioangiomas, we advise regular ultrasound and Doppler examinations, with the aim of detecting fetal anemia before hydrops develops. When anemia is suspected, fetal blood sampling is indicated and intrauterine transfusion therapy may be beneficial to preserve fetal health until maturity is reached.